In-situ crystalline Cr₃C₂ and amorphous SiO₂ dual-particles reinforced NiCr-based composites

Strength and ductility of structural materials are mutually exclusive in general due to the strength-ductility trade-off. Using in-situ pyrolysis of polycarbosilane in NiCr powder green compacts, we fabricated NiCr-based composites with micro-sized crystalline Cr₃C₂ and amorphous SiO₂ dual-particles. Tensile tests show that the NiCr-based composites have a combination of high strength and ductility with the yield strength, ultimate tensile strength and ductility as 449 MPa, 838 MPa and 20.5%, respectively. The amorphous SiO₂ and crystalline Cr₃C₂ particles exhibit plastic deformation and transgranular fracture, respectively, under tensile stress. Besides solid solution strengthening, the generation and annihilation behavior of dislocations at amorphous/crystalline interface and the strain hardening of the ceramic particles by hindering the movement of dislocations mutually contributes to the combination of excellent strength and ductility of our composites.